- Use WITH_SLICES to conditionalize the fdisk editor during install instead

- Use WITH_SLICES to conditionalize the fdisk editor during install instead
  of an explicit list of architecture defines.
- Tweak the message prior to the label editor in the !WITH_SLICES case to
  make it slightly less awkward since this is the first dialog we see after
  starting an install.
- Only offer to customize syscons settings if WITH_SYSCONS.
- Offer to enable Linux compat if WITH_LINUX.  Before we only did this for
  i386.
- On the alpha, offer to enable OSF/1 compat after asking about Linux
  compat.
- Only offer to configure moused(8) if WITH_MICE is defined.

Tested on:	i386, alpha, sparc64
Approved by:	re